HazMat Tool — substance information
Hexaethyl tetraphosphate, liquid
HMT May 2026Hexaethyl tetraphosphate, liquid
Hexaethyl tetraphosphate (also known as HETP) is the organophosphorus compound with the chemical formula Wikipedia
| Emergency Response Guide No. 151 |
Hazardous Materials Table
Source: 49 CFR §172 (2026/05)(3) Hazard Class6.1Poisonous Material |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| IB2 | |
|---|---|
| N76 | |
| T7 | |
| TP2 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 153 | see 49 CFR §173.153 |
|---|---|---|
| (8B) Non-bulk | 202 | see 49 CFR §173.202 |
| (8C) Bulk | 243 | see 49 CFR §173.243 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 5 L |
|---|---|
| (9B) Cargo aircraft only | 60 L |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
(3) Hazard Class6.1Poisonous Material |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
|||||||||||
(7) Special Provisions (§172.102)
|
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| IB8 | |
|---|---|
| IP2 | |
| IP4 | |
| N76 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 153 | see 49 CFR §173.153 |
|---|---|---|
| (8B) Non-bulk | 212 | see 49 CFR §173.212 |
| (8C) Bulk | 242 | see 49 CFR §173.242 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 25 kg |
|---|---|
| (9B) Cargo aircraft only | 100 kg |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
Packing group comparison
Multiple packing groups apply to this entry. See assignment criteria in 49 CFR §173 Subpart D. Details are in the tabs above; differences are highlighted.
Segregation chart for load, transport, and storage
This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.
Note: The HMR prohibit only those Division 6.1 liquids that meet the definition of a Packing Group (PG) I and Hazard Zone A. See special provision 1 and PHMSA Interpretation #09-0252.
Packages with POISON or POISON INHALATION HAZARD labels, or a POISON label displaying “PG III,” or “PG III” marked next to a POISON label may not be transported with foodstuffs, feed or any other edible material, intended for humans or animals. For exceptions see 49 CFR §177.841(e).
Scope & sources (important)Click to show CFR references
This check evaluates segregation per 49 CFR §177.848. Additional loading/unloading and handling requirements may still apply; see 49 CFR §177 Subpart B (Loading and Unloading):
- §177.834 - General requirements
- §177.835 - Class 1 materials
- §177.837 - Class 3 materials
- §177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic liquid) materials
- §177.839 - Class 8 (corrosive) materials
- §177.840 - Class 2 (gases) materials
- §177.841 - Division 6.1 and Division 2.3 materials
- §177.842 - Class 7 (radioactive) material
- §177.843 - Contamination of vehicles
Similar substances
| UN / ID | Proper shipping name | Hazard class |
|---|---|---|
| UN 1612 | Hexaethyl tetraphosphate and compressed gas mixtures | 2.3 |
| UN 1611 | Hexaethyl tetraphosphate, liquid | 6.1 |

